In general, battery relays control battery power supplied to a load side of a vehicle and are primarily applied to medium/large-sized buses. When the battery relays receive power from a power source such as a battery, a bobbin unit therein may generate magnetic force and a movable contact installed in a plunger may contact a fixed contact as an internal plunger is moved by the magnetic force, and as a result, the battery power may be supplied to a load terminal.
For example, FIG. 1 shows a cross-sectional view illustrating a battery relay for a vehicle in the related art.
As illustrated in FIG. 1, the battery relay in the related art is constituted by a movable unit 10 including a plunger 11 and a movable contact 12 integrated, a return spring 21 elastically supporting the movable unit 10 at a lower side of the plunger, a fixed unit 20 supporting a lower part of the return spring 21 and accommodating the movable unit 10, a fixed contact 22 fixedly disposed at a lower side of the movable contact 12, and a bobbin unit 23 disposed on a lower outer peripheral surface of the plunger 11 and selectively connected to a power supply by start on/off of the vehicle.
In the battery relay in the related art, when current flows on the bobbin unit 23 and the movable unit 10 is thus magnetized, the movable unit 10 which is distant from the fixed unit 20 by the return spring 21 may overcome spring force from the return spring 21 by the magnetic force. As such, the movable contact 12 and the fixed contact 22 may contact. In addition, when the fixed unit 20 and the movable unit 10 contact each other, the spring force of an assistant spring 13 installed on the top of the movable contact 12 may be additionally applied. Accordingly, the movable contact 12 and the fixed contact 22 may contact each other with improved force. Upon returning, the movable unit 10 may be moved by the spring force of the return spring 21, and the contact may be released.
Since the battery relays for the vehicles applied to the medium/large sized buses generally may use substantial amount of current, arc generated when the movable contact and the fixed contact contact each other may not be fully removed.
In conventional battery relay, since the movable unit 10 moves by overcoming the spring force with only the magnetic force of the bobbin unit 23 when the battery relay is turned on, the movable unit 10 may be moved by less force than the magnetic force and the movable unit 10 may be moved with reduced magnetic force upon switching (contacting). A movement speed of the movable unit 10 may be low and a switching time may increase when a contact formed between the movable contact 12 and the fixed contact 22. Accordingly, a large amount of arc may be continuously generated at a contact portion between the movable contact 12 and the fixed contact 22. Consequently, fusion of the contact portion may be accelerated.
Moreover, in the battery relay in the related art, the movable unit 10 may return by only the spring force when the battery relay is turned off and a movement time of the movable unit 10 may increase upon returning. Therefore, the contact portion between the movable contact 12 and the fixed contact 22 may receive greater amount of arc and a fusion time of the contact portion may be reduced in accordance with an increase in the amount of generated arc.
Accordingly, there is a demand for an operation structure which may minimize the amount of arc generated upon contact and improve durability of the relay by shortening the switching time between the movable contact and the fixed contact.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.